Python餐厅点餐程序问题：如何查看订单并计算总账单？

我是Python初学者，这是我的第3个程序，正在学习函数。程序需实现用户先从主菜单（1.开胃菜、2.主菜、3.饮品、4.甜点、5.查看订单、6.退出）选择，每个选项包含子选择（例如开胃菜包含沙拉、薯片等），用户选完商品后可返回主菜单。目前我卡在「查看订单」功能上，需要实现显示用户订单中的每个商品及对应价格，最后展示总账单。请问如何查看用户的所有订单？如何计算总金额？是否需要使用循环？

def menu():
  print("--MCQUAN MENU--")
  print("1. Appetizers")
  print("2. Mains")
  print("3. Drinks")
  print("4. Desserts")
  print("5. View order")
  print("6. Exit")
  print()

def user_option():
  choice = int(input("Choose from the menu & enter a number 1-6: "))
  if choice == 1:
    print()
    print("APP - heres the apps")
    print("Salad - $5")
    print("Chips & salsa - $6")
    print("Soup - $10")
  elif choice == 2:
    print("MAINS - here the mains")
    print("Pasta - $13")
    print("Burger - $12")
    print("Pizza - $10")
  elif choice == 3:
    print("DRINKS - heres drinks")
    print("Water - $0")
    print("Tea - $3")
    print("Sprite - $2")
  elif choice == 4:
    print("DESSERTS - heres desserts")
    print("Cake - $6")
    print("Ice cream - $5 ")
    print("Pie - $7")
  elif choice == 5:
    print("VIEW ORDER -- heres ur order so far")
  elif choice == 6:
    print("Exiting")
  else:
    print("Invalid")
    choice = int(input("Enter number 1-6"))

def app():
  cost = 0
  total = 0
  user_food = input("Choose which u want ")
  if user_food == "salad":
    cheese = input("Cheese? (+$0.50) yes/no ")
    dressing = input("Dressing? (+$1) yes/no ")
  elif user_food == "chips & salsa":
    spicy = input("Spicy? yes/no ")
    cilantro = input("Cilantro? yes/no ")
  elif user_food == "soup":
    soup = input("Chicken noodle or mushroom? ")
  else:
    print("Alright!")
  user_option()
  user_food = input("Choose which u want ")

def main():
  user_food = input("Choose which u want ")
  if user_food == "pasta":
    cheese_2 = input("Cheese? yes/no ")
    chilli_f = input("Chilli flakes? yes/no ")
  elif user_food == "burger":
    onions = input("Onions? yes/no ")
    pickles = input("Pickles? yes/no ")
  elif user_food == "Pizza":
    pizza = input("Cheese or pepperoni? ")
  else:
    print("Alright!")
  user_option()
  user_food = input("Choose which u want ")

  def drinks():
    user_food = input("Choose which u want ")
    if user_food == "water":
      size = input("Small, medium or large? ")
    user_option()
    user_food = input("Choose which u want ")
  def desserts():
    user_food = input("Choose which you want")
    if user_food == "cake":
      w_c = input("Whipped cream? yes/no ")
      cherry = input("Cherry? yes/no ")
    elif user_food == "ice cream":
      w_c = input("Whipped cream? yes/no")
      cherry = input("Cherry? yes/no ")
    elif user_food == "pie":
      w_c = input("Whipped cream? yes/no")
      cherry = input("Cherry? yes/no ")
    else:
      print("Alright")
      user_option()
      user_food = input("Choose which u want ")


     
#main
menu()
print("Welcome to McQuans!")
print()
user_option()
app()
main()
drinks()
desserts()

核心问题解答 #

1. 如何查看所有订单：用全局列表存储每个订单项（包含商品名称和价格），每次用户选完商品后将信息添加到列表，查看时遍历列表逐个打印。
2. 如何计算总金额：维护全局总金额变量，每次添加商品时累加对应价格；或查看订单时遍历订单列表，把所有项的价格相加。
3. 是否需要循环：需要。主程序要用循环反复显示菜单，让用户可多次操作直到退出；查看订单时也需要循环遍历订单列表打印商品。

修改后的完整代码 #

# 全局变量存储订单和总金额
orders = []
total_amount = 0.0

def menu():
    print("--MCQUAN 菜单--")
    print("1. 开胃菜")
    print("2. 主菜")
    print("3. 饮品")
    print("4. 甜点")
    print("5. 查看订单")
    print("6. 退出")
    print()

def view_order():
    print("\n--- 你的订单 ---")
    if not orders:
        print("订单为空")
        return
    # 循环遍历订单列表，打印每个商品
    for idx, item in enumerate(orders, start=1):
        print(f"{idx}. {item['name']} - ${item['price']:.2f}")
    # 打印总金额
    print(f"\n总账单: ${total_amount:.2f}")
    print("---------------\n")

def handle_appetizers():
    print("\n--- 开胃菜选项 ---")
    print("沙拉 - $5")
    print("薯片配莎莎酱 - $6")
    print("汤 - $10")
    choice = input("请选择你想要的开胃菜: ").strip().lower()
    item_name = ""
    item_price = 0.0
    if choice == "沙拉":
        item_name = "沙拉"
        item_price = 5.0
        cheese = input("加芝士? (+$0.50) 是/否: ").strip().lower()
        if cheese == "是":
            item_name += "(加芝士)"
            item_price += 0.5
        dressing = input("加调味酱? (+$1) 是/否: ").strip().lower()
        if dressing == "是":
            item_name += "(加调味酱)"
            item_price += 1.0
    elif choice == "薯片配莎莎酱":
        item_name = "薯片配莎莎酱"
        item_price = 6.0
        spicy = input("加辣? 是/否: ").strip().lower()
        if spicy == "是":
            item_name += "(辣)"
        cilantro = input("加香菜? 是/否: ").strip().lower()
        if cilantro == "是":
            item_name += "(加香菜)"
    elif choice == "汤":
        soup_type = input("鸡肉面汤还是蘑菇汤? ").strip()
        item_name = f"{soup_type}汤"
        item_price = 10.0
    else:
        print("无效选择，返回主菜单")
        return
    # 添加到订单
    orders.append({"name": item_name, "price": item_price})
    global total_amount
    total_amount += item_price
    print(f"已添加 {item_name} 到订单!\n")

def handle_mains():
    print("\n--- 主菜选项 ---")
    print("意面 - $13")
    print("汉堡 - $12")
    print("披萨 - $10")
    choice = input("请选择你想要的主菜: ").strip().lower()
    item_name = ""
    item_price = 0.0
    if choice == "意面":
        item_name = "意面"
        item_price = 13.0
        cheese = input("加芝士? 是/否: ").strip().lower()
        if cheese == "是":
            item_name += "(加芝士)"
        chilli = input("加辣椒碎? 是/否: ").strip().lower()
        if chilli == "是":
            item_name += "(加辣椒碎)"
    elif choice == "汉堡":
        item_name = "汉堡"
        item_price = 12.0
        onions = input("加洋葱? 是/否: ").strip().lower()
        if onions == "是":
            item_name += "(加洋葱)"
        pickles = input("加酸黄瓜? 是/否: ").strip().lower()
        if pickles == "是":
            item_name += "(加酸黄瓜)"
    elif choice == "披萨":
        pizza_type = input("芝士披萨还是辣香肠披萨? ").strip()
        item_name = f"{pizza_type}披萨"
        item_price = 10.0
    else:
        print("无效选择，返回主菜单")
        return
    orders.append({"name": item_name, "price": item_price})
    global total_amount
    total_amount += item_price
    print(f"已添加 {item_name} 到订单!\n")

def handle_drinks():
    print("\n--- 饮品选项 ---")
    print("水 - $0")
    print("茶 - $3")
    print("雪碧 - $2")
    choice = input("请选择你想要的饮品: ").strip().lower()
    item_name = ""
    item_price = 0.0
    if choice == "水":
        size = input("小杯、中杯还是大杯? ").strip()
        item_name = f"{size}水"
        item_price = 0.0
    elif choice == "茶":
        item_name = "茶"
        item_price = 3.0
    elif choice == "雪碧":
        item_name = "雪碧"
        item_price = 2.0
    else:
        print("无效选择，返回主菜单")
        return
    orders.append({"name": item_name, "price": item_price})
    global total_amount
    total_amount += item_price
    print(f"已添加 {item_name} 到订单!\n")

def handle_desserts():
    print("\n--- 甜点选项 ---")
    print("蛋糕 - $6")
    print("冰淇淋 - $5")
    print("派 - $7")
    choice = input("请选择你想要的甜点: ").strip().lower()
    item_name = ""
    item_price = 0.0
    if choice == "蛋糕":
        item_name = "蛋糕"
        item_price = 6.0
        cream = input("加鲜奶油? 是/否: ").strip().lower()
        if cream == "是":
            item_name += "(加鲜奶油)"
        cherry = input("加樱桃? 是/否: ").strip().lower()
        if cherry == "是":
            item_name += "(加樱桃)"
    elif choice == "冰淇淋":
        item_name = "冰淇淋"
        item_price = 5.0
        cream = input("加鲜奶油? 是/否: ").strip().lower()
        if cream == "是":
            item_name += "(加鲜奶油)"
        cherry = input("加樱桃? 是/否: ").strip().lower()
        if cherry == "是":
            item_name += "(加樱桃)"
    elif choice == "派":
        item_name = "派"
        item_price = 7.0
        cream = input("加鲜奶油? 是/否: ").strip().lower()
        if cream == "是":
            item_name += "(加鲜奶油)"
        cherry = input("加樱桃? 是/否: ").strip().lower()
        if cherry == "是":
            item_name += "(加樱桃)"
    else:
        print("无效选择，返回主菜单")
        return
    orders.append({"name": item_name, "price": item_price})
    global total_amount
    total_amount += item_price
    print(f"已添加 {item_name} 到订单!\n")

def main_loop():
    while True:
        menu()
        try:
            choice = int(input("请选择菜单编号(1-6): "))
        except ValueError:
            print("请输入有效的数字!\n")
            continue
        if choice == 1:
            handle_appetizers()
        elif choice == 2:
            handle_mains()
        elif choice == 3:
            handle_drinks()
        elif choice == 4:
            handle_desserts()
        elif choice == 5:
            view_order()
        elif choice == 6:
            print("退出程序，感谢光临!")
            break
        else:
            print("无效编号，请输入1-6之间的数字!\n")

# 启动程序
print("欢迎来到McQuans餐厅!")
main_loop()

关键修改说明 #

• 新增全局变量orders（存储所有订单项）和total_amount（存储总金额），实现跨函数共享订单数据。
• 拆分原函数，每个品类单独做处理函数（如handle_appetizers），负责展示选项、收集定制需求、计算价格并添加到订单。
• 新增view_order函数，通过for循环遍历订单列表打印商品信息，最后展示总金额。
• 主程序改为main_loop函数，用while True循环实现反复显示菜单，直到用户选择退出。

内容的提问来源于stack exchange，提问作者coballt27